In-vivo measuring systems are known in the art. Some in-vivo devices/systems that traverse the gastrointestinal (GI) system may include one or more imaging sensors, for imaging (e.g., capturing images of) the interior of the GI system, and/or sensors of other types. In-vivo devices may traverse the GI system by being pushed through the GI system by peristaltic force exerted by the digestive system, or by being maneuvered (e.g., magnetically). Some applications require knowing the current position and/or orientation (P&O) of the involved in-vivo device. For example, in order to magnetically maneuver an in-vivo device, for example in the GI system, the magnetic maneuvering system should know the current P&O (and the target P&O) of the in-vivo device in order to generate the correct steering magnetic fields. Therefore, a localization system may also be used in order to provide localization information to the magnetic maneuvering system, based on which the magnetic maneuvering system can maneuver the in-vivo device. A localization system may generate an alternating current (“AC”) electromagnetic field that may be sensed by electromagnetic field sensors embedded in the in-vivo device. The P&O of the in-vivo device may be determined from the AC signals that the electromagnetic field sensors output.
An advanced maneuvering system may use an AC electromagnetic field and a direct current (“DC”) electromagnetic field to maneuver devices in vivo. Operating an electromagnetic based localization system and an electromagnetic based maneuvering system at the same time may result in mutual interference between the two systems. For example, an external maneuvering AC magnetic field generated by the maneuvering system may have a negative side effect on the readout of the localization electromagnetic field sensors of the in-vivo device, and the external AC localization signal generated by the localization system may have a negative side effect on the maneuvering force that maneuvers the in-vivo device. Therefore, it is preferable that the two systems operate intermittently, with one system (e.g., the magnetic maneuvering system) operated while the other system (e.g., electromagnetic based localization system) is temporarily disabled, and vice versa. However, due to high currents that are usually required to generate maneuvering electromagnetic fields, the electromagnetic field, which may be generated by using a switching circuit/technique, may not be able to be shut down completely in time in, and for, the required time (e.g., when localization sensing takes place). Inability to shut down the maneuvering magnetic field completely on time may result in a residual electromagnetic field that causes electromagnetic field interference, thus to erroneous determination of the P&O of the in-vivo device.
Electrical currents of electromagnetic coils are often controlled by using pulse width modulation (“PWM”). However, using PWM results in switching frequency components superimposed on localization signals during localization time periods. Therefore, it would be beneficial to have a method that would enable a magnetic maneuvering system to steer an in-vivo device and a magnetic localization system to locate the in-vivo device without the maneuvering system interfering with the operation of the localization system.